wasmtime_internal_core/alloc/
arc.rs

1use super::TryNew;
2use crate::error::OutOfMemory;
3use std_alloc::sync::Arc;
4
5/// XXX: Stable Rust doesn't actually give us any method to build fallible
6/// allocation for `Arc<T>`, so this is only actually fallible when using
7/// nightly Rust and setting `RUSTFLAGS="--cfg arc_try_new"`.
8impl<T> TryNew for Arc<T> {
9    type Value = T;
10
11    #[inline]
12    fn try_new(value: T) -> Result<Self, OutOfMemory>
13    where
14        Self: Sized,
15    {
16        #[cfg(arc_try_new)]
17        return Arc::try_new(value).map_err(|_| {
18            // We don't have access to the exact size of the inner `Arc`
19            // allocation, but (at least at one point) it was made up of a
20            // strong ref count, a weak ref count, and the inner value.
21            let bytes = core::mem::size_of::<(usize, usize, T)>();
22            OutOfMemory::new(bytes)
23        });
24
25        #[cfg(not(arc_try_new))]
26        return Ok(Arc::new(value));
27    }
28}
29
30#[cfg(test)]
31mod test {
32    use super::{Arc, TryNew};
33
34    #[test]
35    fn try_new() {
36        <Arc<_> as TryNew>::try_new(4).unwrap();
37    }
38}
wasmtime_internal_core/alloc/arc.rs

wasmtime_internal_core/alloc/
arc.rs
